Six months after proudly announcing that San Diego leads the state in the number of rooftop solar systems, city officials last month made it more expensive to go green by raising its fees sixfold.

The cost of getting a solar installation plan approved and the system inspected has risen to $565 from $93. The increase reflects a policy change by the city to quit subsidizing solar installations and adjust fees to reflect what it costs to issue the permits, officials say.

Solar advocates and installers say the fee increase is unjustified and may hurt efforts to cut carbon emissions that contribute to global warming.

“It doesn’t make a lot of sense,” said Daniel Sullivan, whose San Diego installation business has grown from two employees to 28 in the past five years. “You don’t start taxing the industry that’s growing the fastest just because your general fund is hurting.”

Fees are needed if the industry is to grow, said San Diego Mayor Jerry Sanders.

“The fees, it’s a part of life,” Sanders said. “We wouldn’t have the people up there to process (applications) if we can’t have the fee structure that allows them to support themselves.”

San Diego used to be the third-cheapest place in the county to get a permit for a photovoltaic system, but now it trails only National City — whose fees are $595 — as the most expensive, according to a 2009 Sierra Club survey.

“$565 is way more than they need,” said the Sierra Club’s Carl Mills, who wrote the survey that said any fee higher than $324 was excessive.

Residents of unincorporated communities in San Diego County pay nothing — the county government waives permit fees to encourage solar development.

“In the spectrum of permit fees, $93 was on the low side, while $565 is on the high side,” said Andrew McAllister, director of programs for the California Center for Sustainable Energy, which helps homeowners qualify for state subsidies for solar installations.

The Sierra Club’s survey found a range of fees statewide, with some Los Angeles-area cities the most expensive at around $1,500.

San Diego officials say the revised fees are part of an overall effort to make sure people pay what it costs the city to provide services. They are not related to the city’s general fund.

“We are encouraging solar,” Sanders said. “But one of the things we’ve learned is we get sued when we subsidize one type of development from other developers.”

Sanders said the fee is a fraction of the cost of a solar installation, which can top $30,000.

The city wants to make solar affordable, Sanders said. In a few months, a new program will issue low-cost loans to residents for solar installations. Residents will pay off the loans over 20 years through their property tax bills.

The higher fees and the loans could mean a windfall for the city, said Sullivan, the solar installer.

“If you’re talking about hundreds and hundreds of systems, you’re talking about hundreds of thousands of dollars of impact to the San Diego economy,” he said.